Politoed
Politoed is good but I don't know why you have 4 Speed EV's? I mean it can take a hit and it's not going to outspeed anyone soon. Go for SpD EV's. The moves and all are good :D
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Thundurus-Therian
Thunderus-T, while good at sweeping, lacks some base speed even with Timid. Agility might suit you better, but not that I don't think Nasty Plot is bad or anything. Also, I prefer Focus Blast over Grass Knot, it covers more and Thunder covers Water anyway. Anyway, I think a Scarf or Agility will be better, but it's your choice ;)
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Cloyster
While good, Focus Sash is useless, 80% of the time on your team. Since you don't have a spinner, and the growing use of SR and Spikes and Toxic Spikes, Focus Sash goes bye-bye. Have Life Orb or White Herb. Also, I think you're mixing two different roles into one. Spinner and Shell Smasher doesn't go well. Either have one, or the other. So like I said, if you want to go with Spinner, it's Defense comes into play. You can also use it as a POke to lay out Spikes.
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Tornadus-T
Why go with Timid when you have Scarf? That makes no sense, plus Modest gives it enough juice to hit extra hard. But, Tornadus-T is a great Life Orb abuser, the Regenerator heals back any damage done to it. Also, Specs is an option. Just saying.
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Dragonite
No comment, it's good as it is :D
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Scizor
Why Pursuit. I know it gets Technician boost, but something like Superpower hits extremely hard, even to resist, after some Swords Dance's. And, Life Orb is an option.
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Nice team overall, just know that you don't have a lot of walls. But you already know that ;) Good team, and good luck with it.
